A multidisciplinary team led by Dr. A. J. Colussi, comprising of graduate student Himanshu Mishra, and Professor Michael Hoffmann along with Dr. Robert J. Nielsen and Professor William A. Goddard III from the Materials and Process Simulation Center, has shown that the dissociation of nitric acid on thin layers of water, such as those in contact with air or biological membranes, is dramatically different from the similar process inside water. They have found that the molecules of nitric acid do not dissociate when they collide with water unless its surface contains at least 1 anion per million water. This work explains how minute concentrations of anions might subtly participate in acid rain chemistry, the cycling of nitrogen oxide pollutants on urban haze, and in the charging of protein surfaces that drive enzyme activities. [The PNAS Article]

By analyzing stalagmites, Jess F. Adkins, Professor of Geochemistry and Global Environmental Science, and colleagues have determined that the climate signature in the tropics through four glacial cycles looks different in some ways and similar in others when compared to the climate signature at high latitudes. The results suggest that Earth's climate system might have two modes of responding to significant changes. [Caltech Press Release]

John H. Seinfeld, Louis E. Nohl Professor and Professor of Chemical Engineering, and past Engineering and Applied Science Division Chair has recieved the Tyler Prize for Environmental Achievement, an honor regarded as the top prize of environmental science, environmental health, and energy. He has won the prize for "his groundbreaking work leading to the understanding of the origin, chemistry, and evolution of particles in the atmosphere." [Caltech Feature]

A new computer model of the atmosphere and methane cycle of Titan, Saturn's largest moon, explains baffling observations of its lakes and storms. "We have a unified explanation for many of the observed features," says Tapio Schneider, the Frank J. Gilloon Professor of Environmental Science and Engineering. "It doesn't require cryovolcanoes or anything esoteric." [Caltech Press Release]

Andrew Thompson, Assistant Professor of Environmental Science and Engineering, joined the Caltech Division of Geological and Planetary Sciences in August 2011. His research focuses on eddies in the ocean which are important for mixing the ocean and transporting heat, chemicals, and biological elements. [Caltech Press Release]

Tapio Schneider, Frank J. Gilloon Professor of Environmental Science and Engineering, and Dr. Yohai Kaspi have found a mechanism that helps explain why average winter temperatures in northern Europe are at least 10 degrees Fahrenheit warmer than similar latitudes on the northeastern coast of the United States. Using computer simulations of the atmosphere, they have found that the warm water off an eastern coast will heat the air above it and lead to the formation of atmospheric waves, drawing cold air from the northern polar region. The cold air forms a plume just to the west of the warm water. In the case of the Atlantic Ocean, this means the frigid air ends up right over the northeastern United States. [Caltech Press Release]

Ares J. Rosakis, Theodore von Kármán Professor of Aeronautics and Professor of Mechanical Engineering, and Michael R. Hoffmann, James Irvine Professor of Environmental Science have been elected to the National Academy of Engineering (NAE). Professor Rosakis was elected for discovery of intersonic rupture, contributions to understanding dynamic failure, and methods to determine stresses in thin-film structures. Professor Hoffmann was elected for oxidative treatment technologies for the removal of organic and inorganic contaminants from water.